The semiconductor industry has experienced exponential growth. Over the course of the growth, functional density of the semiconductor devices has increased with the decrease of device feature size or geometry. The scaling down process generally provides benefits by increasing production efficiency, reducing costs, and/or improving device performance, but increases complexity of the integrated circuit (IC) manufacturing processes.
To address the increase of manufacturing complexity, various non-planar transistors, such as a fin-like field-effect transistor (FinFET), have been developed to replace a planar transistor. However, device performance of such FinFET is still not satisfactory in advanced applications of technology. Therefore, improvements in structures and methods of forming a FinFET with better device performance continue to be sought.